The invention relates to a fluid damper, in particular for moving furniture parts, with a cylinder and a piston linearly displaceable therein. The piston has at least one opening for a damping fluid provided in the cylinder, and has at least one movable ring disk in the area of the opening(s). Such fluid dampers are used in order, for example, to damp out the closure motion of moving furniture parts such as furniture doors, shutters or drawers, in the rearmost closing area.
According to the known state of the art, the cylinder is preferably attached to the furniture body, for example a furniture side or a furniture base, and the furniture doors or the front panel of a drawer strikes the piston rod of the piston during closing. The damping results from the flow resistance of the damping fluid when the piston is displaced. A hydraulic fluid, for example an oil (silicone oil), is preferably used as damping fluid. However gases, in particular air, can also be used.
The object of the invention is to improve a fluid damper of the type mentioned at the outset such that its damping-out action is better matched to the speed of the moved furniture part.
The object according to the invention is achieved by arranging the at least one ring disk such that it at least partially covers the opening(s) during the damping stroke of the piston.
An embodiment of the invention provides that the ring disk(s) is or are elastically bendable during the damping stroke.
It is advantageously provided that the ring disks have different rigidities, which is achieved for example by the ring disks having different thicknesses or being made of different materials.
A further embodiment of the invention provides that the piston is fitted with a pin on which the ring disks are housed so as to be axially displaceable. Springs are provided which, in the resting position of the piston, separate the ring disks from the piston and from one another. Three or four elastically movable ring disks are preferably provided.
Upon insertion of the piston rod, the hydraulic fluid flows through the ring gaps between the ring disks and the cylinder wall and through the openings in the piston. Depending on the speed of the moved furniture part and thus of the piston, the elastically bendable ring disks are bent back as a result of the flow resistance or the springs between the ring disks are compressed. The greater the flow resistance thus produced, the smaller the effective throughflow diameter of the openings as the front ring disk in each case partly or fully covers the openings of the rings located behind it. The speed of the piston decreases accordingly. If the piston slows, the flow resistance also becomes smaller and the ring disks move back into their starting position, as a result of which the effective diameter of the openings is enlarged.